Metallurgical furnace



(No Model.) A f 2 Sheets-Sheet 2.

G. E'. SIMONDS. METALLURGIGAL FURNAGL No. 507,460. Patented oct. 24,189s.

UNITED STATES PATENT OFFICE.

GEORGE F. SIMONDS, OF FITOHBURG, MASSACHUSETTS.

AIVIETALLURGICAL FURNACE.

SPECIFICATION forming part of Letters Patent No. 507,460, dated October24, 1893. Application led December 17, 1892. Serial No. 455,483. (Nomodel.)

T0 all whom/.llt may concern:

Be it known that I, GEORGE F. SIMoNDs, a citizen of the UnitedStates,residing at Fitchburg, in the county of Worcester and State ofMassachusetts, have invented new and useful Improvements inlvletallurgical Furnaces, of which the following is a specification.

This invention relates to furnaces for tempering or annealing and otheroperations requiring a working chamber or oven that can be uniformlyheated throughout and in which the desired uniform temperature can bemaintained.

My invention consists in a furnace having a working chamber surroundedby a heating chamber and an intermediate closed dead air space,preferably in the form of a tortuous passage, in contact withsubstantially all sides of the working chamber and with which a fancommunicates for the purpose of causing a constant circulation of heatedair throughout said intermediate closed space or tortuous passage andthereby maintaining a uniform toemperature in all parts of the workingcham- The invention also consists in the features of construction andnovel combinations of parts in a tempering or Vannealing furnace ashereinafter set forth.

In the annexed drawings illustrating the invention-Figure 1 is asectional side-elevation of my improved furnace with portions of theinner and outer Walls of the working chamber broken away. Fig. 2 is aperspective of the box or shell forming the inner wall of the workingchamber. Fig. 3 is a similar view of the box or shell forming the outerWall of the working chamber. Fig. 4. is a horizontal section of onecorner of the working chamber and surrounding dead air spaces orpassages.

Referring to Fig. 1, the numeral 1 designates the ash-pit; 2 the grateand 3 the combustion chamber. The furnace is constructed wit-hnon-conducting inner and outer Walls of fire brick 4, preferably havinga dead air space or spaces 5 between the inner and outer walls and acoating or filling 6 of cement or suitable non-conducting materialinclosed in the outer Walls.

In the upper part of the combustion chamber 3 are brackets 7 supportinga horizontal diaphragm 8 which forms the door of a heating chamber 9that constitutes the upper part of the furnace. The diaphragm 8 does notextend to the Walls of the furnace but is so arranged as to leave lines10 at the front and rear and on both sides for the upward passage of theproducts of combustion into the heating chamber. On each side theheating chamber communicates, through an opening 1l, With tlues 12 builtin the furnace Walls and connecting with an exit flue 13 at the rear.

The heating chamber 9 contains a Working chamber 14 constructed withdouble walls between which several series of dead air spaces 15 areinclosed. These air spaces 15 communicate with each other and with arotary fan 16 that is arranged in an enlarged portion 17 of one of saidspaces. The fan 16 is provided with a shaft 18 extended to the outsideof the furnace and having a pulley 19 thereon through which the fan canbe rotated for the purpose of causing a continuous circulation of theheated air inclosed in the communicating spaces 15 and therebyequalizing the temperature of all parts of the Working chamber.

I prefer to construct the working chamber 14 in the form of two metallicshells or boxes, as 20, Fig. 2, and 21, Fig. 3, one arranged or nestedwithin the other as shown in Fig. 1. These shells or boxes 2O and 21 mayeach have a rectangular form to correspond with the substantiallyrectangular interior of the heating chamber 9 in which the workingchamber 14 is placed. The outside of the inner box or shell 20, formingthe inner wall of the working chamber, is provided with llanges orribbed projections 22 of varying length and disposed on all sides insuch directions and at such intervals as to form with the smoothinterior of the outer box, shell or wall 21 several series ofcommunicating spaces 15 that thus constitute a tortuous passage for theinclosed heated air circulated by the fan 16 in contact with all partsof the surface of the Working chamber, as indicated by the arrows inFigs. 1 and 2. It will be understood that the heated air thus circulatedin the tortuous passage or communicating air spaces 15 between thedouble walls of the working chamber iswhollyconiined to said spaces andhas no inlet or outlet and no communication'with the atmosphere nor withany part of the furnace.

rIhe rotary fan 16 for causing a continuous circulation of heated air inthe communicat- 1ng spaces 15 is preferably located in one of the rearupper corners of the outer box or shell 21, the said outer box or shellbeing slightly enlarged at that point to form a fan casing 17 as shownin Figs. 3 and 4. One of the flanges or ribs 22 of the inner box 0rshell 20 1s cut away at 23, Fig. 2, for the purpose of forming a draftopening in which the fan 16 is received when the inner and outer shellsare brought together.

The outer box or shell 21, forming the outer wall of the workingchamber, may be pro' vided on its outside, as shown in Fig. 3, withenclrchng flanges or ribbed projections 24, formlnglseparate passages 25which communicate directly at all points with the heating chamber 9 andthus serve to assist in equallzing the distribution of heated productsof combustion in contact with all parts of the outer wall of the workingchamber. Bythus p rovlding for a somewhat equalized distribut1on of theheated products of combustion passing through the heating chamber 9 theheat 1s economized and the confined air in the space or tortuouspassages 15 between the walls of the working chamber will be morequickly heated. The continuous circulation of this heated air throughthe closed tortuous passages or spaces 15 in contact with all parts ofthe working chamber, by the action of the fall 16, permits themaintenance throughout Said chamber of a steady and uniform temperaturewhich is so essential in order to obtain satisfactory results intempering or annealing and other operations in which a perfectly uniformheat is desirable.

As shown in Fig. 1, the Working chamber 14 is provided with a tightlyclosing door 26 4o of any suitable non-conducting construction.

What I claim as my invention isl. In a furnace, the combination with aworking chamber having double walls between which a dead air space isinclosed, of a rotary fan located in said dead air space for the purposeof causing a continuous circulation of heated air therein to equalizethe temperature of the Working chamber, substantially as described.

2. In a furnace, the combination with a working chamber, and dead airspaces surrounding said chamber and communicating with each other toform a tortuous passage for heated air, of a fan communicating with Saidspaces or tortuous passage for the purpose of causing a continuouscirculation of heated air therein to equalize the temperature of theWorking chamber, substantially as described.

3. In a furnace, the combination of a combustion chamber, a heatingchamber communicating with the combustion chamber, a working chamberlocated in the heating chamber and provided with double walls betweenwhich a closed dead air space is inclosed, and a fan communicating withsaid dead air space and adapted to cause a continuous circulation ofheated airtherein for the purpose of equalizing the temperature ot' theworking chamber, substantially as described.

In testimony whereof I have hereunto set my hand and aflixed my seal inpresence of two subscribing witnesses.

GEORGE F. sIMoNDs. [1.. s]

Witnesses:

GEO. W. REA, T. A. GREEN.

